Very Smooth SiO2/SiC Interface Formed by Supercritical Water Oxidation at Low Temperature

We have formed a SiO 2 layer on a SiC surface by supercritical water (SCW) oxidation at a much lower temperature (400 \mbox{ \circ C}) than that of conventional SiC thermal oxidation (1100 \mbox{ \circ C}). This rapid oxidation at a low temperature is attributed to the high density of the oxidizers (H 2 O and O 2 ) under a high-pressure condition. We also revealed that SCW oxidation under suitable conditions suppresses the formation of SiO 2 /SiC interface microroughness. The smooth SiO 2 /SiC interface obtained by this low-temperature oxidation process is expected to contribute to improving the mobility performance of future SiC field-effect transistors (FETs).